In a sequential fuel injection system of an internal combustion engine the "trigger" or control signal will need to carry two types of information: (1) information to control the actual timing of injection and (2) information for the steering of the injection signal to the proper cylinder of th engine. In such a system, injection must be initiated after so many degrees of crankshaft rotation, for example, every 90.degree. of cranshaft rotation in the case of a V8 engine.
The developed injection timing information must be steered to the proper cylinder in a sequential fuel injection system. This fact implies that the steering information must be related to the camshaft. Steering information would synchronize the injection pulse immediately following, for example, a steering pulse on a selected cylinder and a ring counter could distribute the following injection pulses to the proper injectors according to the engine's firing order.
The U.S. Pat. No. 3,809,029 of Wakamatsu et al., discloses an ignition and fuel injection timing system. Part of the system consists of a means of obtaining fuel injection timing information. One sensor is provided for each cylinder to obtain the fuel injection information. The circuit which controls the triggering of any one injector receives signals from two of the sensors. Sensible elements on a disc connected to the camshaft of the engine are sensed. The sensible elements include a reference element having a width different from the nonreference element. All of the elements are separated by equal spaces. The triggering of each individual injector is initiated by the passage of the reference element under the sensor associated with that injector. The non-reference elements function as countable items to obtain appropriate phase shifts in triggering. An electric integrator and a comparator produce a reference or sync pulse.